Motor centrifugal cut-out switch



June 26, 1934. J. J. JANCA, JR

I MOTOR CENTRIF'UGAL CUT-OUT SWITCH Filed Sept. 6, 1930 2 Sheets-SheetJune 26, 1934. J. J. JANCA. JR

MOTOR CENTRIFUGAL CUT-OUT SWITCH I Filed Sept. 6, 1930 --2 Sheets-Sheet2 Patented June 26, 1934 PATENT OFFICE 1,964,581 moron css'rnrrucsr.cur-our SWITCH Joseph J. Janos, as, St. Louis, Mo., alslgnor to TheEmerson Electric M! a corporation of Missouri Application September s,mo, Serial No. 480,129 7 8 Claims. (01. 172-279) This invention relatesto an improvement in w cut out switches for split phase inductionmotors, and particularly to a switch adapted to automatically cut outthe starting windings and to shunt out a reactance coil alter the motorhas attained at predetermined speed. .One of the objects of thisinvention is to p vide an improved automatic switch to shunt out areactance coil which is arranged in circuit with the main windings atstarting and at low speed.

Another object of this invention is to provide improved mechanismautomatically operable at substantially the same time to cut out thestarting windings and shunt out a reactance coil in an is inductionmotor.

Other objects will be apparent from the following detail description andthe accompanying drawings.

Fig. 1 is a circuit diagram of an induction motor including the switchesorganized in accordance with this invention, with the switch connectionsin the positions assumed at starting and at low speeds.

Fig. 2 is a view similar to Fig. 1 with the switch connections in theirpositions at high speeds.

Fig. 3 is a side elevation of the switchmechanism.

Fig. 4 is a vertical section on line 4-4, Fig. 3.

Fig. 5 is a vertical section on line 55, Fig. 3.

so The invention can best be described by first describing the motorcircuits and the switch connections. In this preliminary descriptionrelerence may be made principally to Figs. 1 and 2 in which are showndiagrammatically the windings,'

5 their connections and the switch connections.

Fig. 1 illustrates the positions 0! the switch terminals at starting andat low speeds, and Fig. 2 at high speeds.

The secondary oi the motor may comprise the ordinary squirrel cagearmature 1. The primary comprises the main windings 2 and the auxiliarystarting windings 3. A reactance coil 4 is connected in series with themain windings 2. As specifically illustrated in the drawingsone mainline lead 5 is connected to one side of one winding 2 and the other mainline lead 6 is connected to one side of the'reactance coil 4. The leads7 and 8 are provided on each side 01' the reactance coil 4 and connectedrespectively to the terminals 9 and 10. A conductor bar 11 is providedto connect the terminals 9 and 10 and thus shunt out the reactance coil4. The details of the mechanism for automatically accomplishing thisresult will be more particularly described in later 55 paragtaphs' r.00., st. Louis, m.

The auxiliary windings 3 are connected in series to the leads 5 and 6through a switch including the terminals 12' and a'conductorring 13. Thearrangement is such that at starting and at low speedsthe conductor ring13 connects the termico nals 12, thus putting the auxiliary windings 3in circuit with the main leads 5 and 6, and the bar 11 is retained awayfrom the terminals 9 and 10, so that the reactance c0114 is in circuitwith the main windings.- Upon an increase in speed, as mechanism isprovided which will be presently described, that automatically causesthe conductor ring 13 to move away from and break contact betweenterminals 12, and to move the conductor bar 11 into contact with theterminals 9 and 10, thus shunting out the reactance coil 4. The utilityoi the auxiliary windings and the re-' actance coil in starting is wellknown and need not be described in detail.

In the drawings, Figs. 3, 4 and 5, representing 15 the details 01 theswitch mechanism, an armature core 14 is secured to and supported by ashaft 15. A sleeve 16 mounted on one end of the shaft 15 carries a disk17 o! non-conductive material which in turn supports the conductor ring13 concentric with the armature shaft, and adapted to contact withtheterminals 12.

A yoke element 19 includes a central sleeve portion 20 rigidly securedto and about the sleeve 18, an annular flange 21 which fits against thenon-conductive disk 17, and the inclined legs 22 which have bifurcatedends 23 fitting about and guided by the pins 24 secured to the armaturecore 14. A spiral spring 25 fltsabout the sleeve 16 and the sleeveportion 20 01' the yoke element and has one end abutting the flangeportion 21 of the yoke element and the other end abutting the armaturecore 14. An outer flange 26 on the sleeve 16 together with the flange 21on the yoke element 19 serves to hold and position the nonconductivedisk 17 and its supported conductor ring 13. It will thus be seen thatconductor ring 13 is normally held in extended position away from thearmature core 14, but by pressure upon the inclined portions 22 01' theyoke element 19 the 1 conductor ring 13 will be withdrawn inwardlytowards the armature core against the tension of the spring 25.

A pair of levers 27 are each i'ulcrumed on a pin 28 which is secured tothe armature core 14. 5 Each of the levers 27 has an arm 27a, whichrests upon the inclined portion 22 01' the yoke element, and a weightedarm 29. A spring 30 holds the lever normally in a position in which theedge of the arm 27a engages the pin 24. Upon rotation no of thearmature, the arm 29 of the lever 27 tends to swing outwardly againstthe tension of the spring 30, causing the -arm 27a to press against theinclined portion 22, thus withdrawing the conductor ring 13.

A plate 31 formed of non-conductive material is secured to the innerside of the end plate of the motor and carries the overhanging terminals9 and 10 which are attached, respectively, to the leads 7 and 8. A yokemember 32 is resiliently secured to the plate 31 and comprises a topmember 33 of non-conductive material and a pair' of legs 34 of resilientconductive material which have ends bent over and secured to the plate31 by screws 35, as best shown in Fig. 3. Each of the legs 34 supports aterminal 12 adapted to contact with the conductor ring 13. The lead 5 isattached to one of the legs 34 and a lead 36 connected to one side ofthe auxiliary windings is attached to the other leg 34. Thus, when theconductor 13 forms a connection between the terminals 12 the auxiliarywindings are connected in circuit to the main leads.

The plate 33 carries at its upper end the conductor bar 11 adapted tocontact with the terminals 9 and 10. The construction and mounting ofthe yoke element 32 is such that when unrestrained the conductor bar 11contacts with the terminals 9 and 10, thus shunting out the reactancecoil 4 and this is the position of the switch mechanism when theconductor ring 13 is withdrawn due to the action of the weight 29 flyingoutwardly due to centrifugal force upon fast rotation of the armature.At starting and at low speeds the conductor ring 13 contacts with theterminals 12 pressing the yoke element 32 out of its normal position sothat the conductor bar 11 is out of contact with the terminals 9 and 10.

It will thus be seen that in starting the conductor ring 13 is incontact with the terminals 12 pressing the yoke element which carriesthe terminals 12 out of its normal position breaking the contact betweenthe terminals 9 and 10 and the conductor bar 11. In this position, asillustrated in Fig. l, the auxiliary windings are in circuit with themain line leads and the reactance coil 4 is in circuit with the mainwindings. At high speeds, due to the action of the weighted arm 29, theconductor ring 13 is withdrawn from the terminals 12, permitting theyoke member 32 to assume its normal position making contact between theterminals 9 and 10 and the conductor bar 11, thus cutting out theauxiliary windings and shunting out the reactance coil 4; the positionof the mechanism being such as is diagrammatically illustrated in Fig.2.

It is apparent that parts of the invention may be used without thewhole, and that various.

changes may be made in the details of construction within the scope ofthe appended claims without departing from the spirit of this invention.

I claim:

1. In an electric motor having a reactance coil in circuit with the mainwindings on the stator and a pair of leads adapted when connected toshunt out the coil, a starting switch comprising a terminal attached toeach of the leads, a frame resiliently mounted on the stator, aconductor secured to the frame and adapted in the released position ofthe frame to contact with said terminals, and means on the rotorresponsive to centrifugal force adapted at starting and at low speeds tocontact with the frame and hold the conductor out of contact with theterminals and at high speeds to permit the frame to assume its releasedposition.

2. In an electric motor having a reactance coil in circuit with the mainwindings and leads adapted when connected to shunt out the react- 30ance coil, a starting switch comprising a pair of terminals connected tosaid leads respectively, a support resiliently mounted on the stator andhaving a conductor yieldingly held against the terminals, a ringconcentric with the motor shaft 35 and adapted for movement therealong,a resilient member for normally holding the ring against the support todisengage the conductor for the terminals, and means responsive tocentrifugal force induced by rotation of the motor armature to withdrawthe ring and release the support.

3. In an electric motor having a reactance coil in circuit with mainwindings and leads-adapted when connected to shunt out the reactancecoil, 8. starting switch comprising a support resiliently mounted on thestator and having a conductor yieldingly held against the terminals, asleeve about the motor shaft supporting a ring concen trio with theshaft, movable weights pivotally supported on the armature of the motor,engaging 00 arms on the sleeve and the weights whereby due tocentrifugal force the weights cause the sleeve and the ring to movelongitudinally along the shaft and release the support.

4. In an electric motor having a stator, a rotor, 05 a shaft, mainwindings, auxiliary windings, a reactance coil in circuit with the mainwindings and leads adapted when connected to shunt out the reactancecoil, a starting switch comprising a frame yieldingly mounted on one endof the stator, a pair of terminals connected to said leads respectively,a contact member on the support yieldingly held in contact with theterminals, a plurality of contacts fixed to the frame and adapted whenconnected to close a circuit to the auxiliary windings, a conductingring concentric with the shaft and movable therealong adapted to engagethe contacts and move the frame, and means responsive to centrifugalforce induced by rotation of the armature to move the ring along theshaft.

5. In an electric motor having a stator, a rotor, a shaft, mainwindings, auxiliary windings, a reactance coil in circuit with the mainwindings and leads adapted when connected to shunt out 5 the reactancecoil, a starting switch comprising a non-conductive plate secured to thestator, a support resiliently mounted on the plate and having aplurality of contacts adapted when connected to close the circuit to theauxiliary windings, a psi of terminals secured to the plate and attachgo said leads respectively, a conductor secured .o the support andadapted when the support is released to contact with the terminals, aconducting ring slidably mounted on the shaft and adapted to engage saidcontacts and to move the support out of its released position, and meansoperable by centrifugal force induced by rotation of the rotor to movethe ring along the shaft.

6. In an electric motor having a stator, a rotor, a shaft, mainwindings, auxiliary windings, a reactance coil in circuit with the mainwindings and leads adapted when connected to shunt out the reactancecoil, a starting switch comprising a yoke resiliently mounted on thestator and having a plurality of contacts adapted when connected toclose the circuit to the auxiliary windings, a conductor secured to theyoke and adapted when the yoke is released to contact with a pair ofoverhanging terminals non-conductively secured to the stator andattacned to said leads respectively. a conducting ring slidablysupported on the shaft and adapted for movement therealong, said ringbeing positioned to engage said contacts and to move the yoke out of itsnormal position. and means operable by centrifugal force induced byrotation of the motor to move the ring.

7. In an electric motor having a stator, a rotor, a shaft, mainwindings, auxiliary windings, a reactance coil in circuit with the mainwindings and leads adapted when connected to shunt out the reactancecoil, a starting switch comprising a non-conductive plate secured to thestator, a support yieldingly secured to the plate and having a pluralityof contacts adapted when connected to close a ircuit to the auxiliarywindings, a conductor s1 cured to the support and adapted when thesupmrt is released to contact with a pair of overhanging terminalssecured to the plate and conductively attached to said leadsrespectively, a conducting ring slidably mounted on the shaft andadapted for movement therealong, said ring being positioned to engagesaid contacts and to move the support out of its normal position,resilient means to hold the ring in engaging position,

and means operable by centrifugal force induced by rotation of the rotorto withdraw the ring.

8. In an electric motor having a stator, a rotor, a shaft, mainwindings, auxiliary windings, a reactance coil in circuit with the mainwindings and leads adapted when connected to shunt out the reactancecoil, a starting switch comprising a non-conductive plate secured to thestator. a yoke resiliently mounted on the plate and having a pluralityof contacts adapted when connected to close a circuit to the auxiliarywindings, a conductor secured to the yoke and adapted when the yoke isreleased to contact with a pair of overhanging terminals secured to theplate and conductively attached to said leads respectively, a

conducting ring non-conductively supported by a sliding sleeve on theshaft and adapted tor movement therealong, said ring being positioned toengage said contacts and to move the yoke out of its normal position.resilient means to hold the ring in engaging position, and meansoperable by eentrirugal force induced by rotation of the rotor towithdraw the ring.

JOSEPH J. JANCA, Jr.

